at a training center for the customs and border protection agency in front royal, virginia, five dogs are running through a series of tests, no matter that it is 90 degrees outside. >> it's going to be hot and tired out there in the field. and we are looking for dogs that when it's hot and tired, they're still going. >> reporter: dhs has 2,000 dogs but just announced it needs 3,000 more. >> we are searching for terrorist, terrorist weapons, illegal immigrants entering the country, being smuggled in and contraban. the dogs can perform those screens and search for those faster than by hand. >> levi the dutch spep heard seems to do well at first. he is given the scent of an object, at this case a pipe and set loose to find it. but searcher and retrieve skills aren't enough. the dogs need courage. they can't spook easily. and they need a good work ethic. that may be levi's undoing. he is supposed to stop at nothing to get at the toy inside the cage but he's easily distracted. his fellow canines aren't doing much better. enzo is supposed to ignore a bowl of food and go for the toy but the